1. Field of the Invention
The present invention relates to ESD (Electro-Static Discharge) events and other occurrences that cause electronic systems to fail; and more particularly to the detection of the failure and the recovery therefrom.
2. Background Information
Modern electronic circuitry is smaller, denser and susceptible to ESD events causing circuit failures. ESD events are often caused by charged human touching a circuit or by other power anomalies, e.g., lightning. Other types of circuit failures may be due to noise, improper resets or a partial power down, improper power up timing, human handling (but less than an ESD shock), and the result may include power supply droop and logic signal blips (a voltage dip or rise) that cause logic malfunctions. For example, a master/slave configuration may fail if the slave and the master were both set into a sending or both into a receiving mode by some anomalous event. In this example, if an event within the slave forced the slave to go into a power down mode without affecting the master, the master may never be aware of the malfunction. It would be advantageous to detect and recover to a normal operating status if this were to happen.
Often a failed circuit (even if the cause was an ESD event) is not permanently damaged. In such cases it would be advantageous to detect the failure and automatically recover to a normal circuit operation.
Others have addressed failures due to ESD events. For example, U.S. Pat. No. 6,658,597 ('597) senses an ESD event and specifically describes power up resetting of a micro-processor (and controllers) into a known state to ensure proper operation resumes. The '597 patent monitors power rails in the circuitry to detect ESD caused failures, and provides for automatic recovery therefrom. The '597 does not address non-ESD failures.
It is advantageous to recover from ESD events, but it would be advantageous to also detect and recover from non ESD event, e.g., power droops, and/or logic blips that do not rise to an ESD-type failure or failures due to some other external factors.